Guide and sewing device for fabric layers along a shaped edge

ABSTRACT

An improved apparatus for guiding layers of fabric to be sewn along an edge of irregular configuration having clamping members for moving the work along a support plane to a sewing machine. The apparatus includes sensing elements for detecting irregularities in the edge to be sewn and devices operatively associated with the sensing elements for orienting the work as it is advanced to the sewing machine, reducing the speed of the sewing machine while sewing in the area of a variation in the fabric edge and returning the sewing machine to normal operating speed upon completion of the sewing in the area of the variation.

United States Patent Marforio Oct. 14, 1975 [54] GUIDE AND SEWING DEVICE FOR FABRIC 3,650,229 341972 Rovin l l2/204 X ERS no A E 3,752,097 8 I973 Fulleretal. 1|2/1s3 x LAY NG 8 ED 3,799,087 3/ l974 Beamish et al. ll2/205 X [75] Inventor: Nerino Marlorio, Milan, Italy [73] Assignee: Vlrglnlo Rimoldl and C. S.p.A., Primary ExaminerH. Hampton Hunter Milan, Italy [22] Filed: May 9, 1974 57 ABSTRACT [21] Appl' 468,457 An improved apparatus for guiding layers of fabric to be sewn along an edge of irregular configuration hav- 30 Foreign A fl fi p i i D ing clamping members for moving the work along a May 22 973 Italy 2436-73 support plane to a sewing machine. The apparatus includes sensing elements for detecting irregularities in 521 US. Cl. 112/153- 1 12/205- 112/219 A the edge be and devices Pemive|y mined [51] Int Cl 2 D0533 35/10, b 27/10 with the sensing elements for orienting the work as it [58] Fieid 1 12/153 3 204 205 is advanced to the sewing machine, reducing the speed l2/220 of the sewing machine while sewing in the area of a variation in the fabric edge and returning the sewing [56] References Cited machine to normal operating speed upon completion of the sewing in the area of the variation.

4 Claims, 5 Drawing Figures Sheet 1 of 4 U.S. Patent Oct. 14, 1975 US. Patent 0a. 14, 1975 Sheet 2 of 4 3,911,840

U.S.Patent Oct. 14; 1975 Sheet 3 of4 US. Patent Oct. 14, 1975 Sheet40f4 3,911,840

GUIDE AND SEWING DEVICE FOR FABRIC LAYERS ALONG A SHAPED EDGE BACKGROUND OF THE INVENTION The present invention is concerned with improvements in an apparatus for guiding and sewing layers of fabric along an edge of any type.

In particular, the improvements in question make it possible to stitch together two or more layers along perfectly overlapped edges characterized by a curving shape and by the frequently varying direction of the recesses.

A type of apparatus is known, to which the improvements in question refer, consisting of a support plane for the work, in one corner of which a sewing machine is installed, e.g. of the cut-and-seam type.

Suspended above the support plane of the work and in front of the sewing machine, a device is provided for guiding and clamping the layers of material which includes two parallel tracks rotatable about a vertical axis and disposed on a horizontal plane parallel to the plane of the work. A pair of clamping members are slidably carried on these tracks and are capable of holding back the layers of the material so that the actual edges to be sewn are perfectly matched.

The material is moved over the support plane of the work by means of lower feeding devices on the sewing machine and possibly also by means of upper feeding devices disposed forwardly or rearwardly of the sewing mechanism.

In front of the sewing machine and in the vicinity of its upper sewing machanism, two photoelectric cells are provided which are positioned at a distance from each other transversely to the direction in which the material to be sewn is advanced.

During the sewing phase, the profile of the edge of the material to be sewn must be constantly maintained between the two photoelectric cells in order to properly guide the material towards the sewing mechanism; consequently one of the photoelectric cells must always be dark and the other always lighted.

In the event that during the sewing phase the two photoelectric cells are both made dark or light according to whether the profile of the material has curves or recesses, one of the photoelectric cells controls a pneumatic mechanism which acts on the rotatable tracks, so as to vary their position accordingly.

Varying the direction or position of the tracks also varies the direction of the fabric clamping members which move along these tracks and additionally the direction of the edge of the material held by the fabric clamping members.

The edge of the material is therefore brought back between the two photoelectric cells more of less quickly according to the inertia of the pneumatic mechanism and of the rotatable tracks.

It is noted that the apparatus briefly described above cannot successfully make stitches along edges with a very irregular profile, i.e. having continuously and unexpectedly varying curves and recesses.

This is due to the fact that, in order to reduce the operating time, the present sewing machines sew at a high 'speed while the rotatable tracks, having a substantial inertia, are not able to instantaneously follow abrupt variations in the profile of the work.

More precisely, it is frequently observed that, whenever one of the photoelectric cells activates the pneumatic mechanism that causes the tracks to rotate, be fore the material moves,the profile of the material itself changes again and displays new curves or cavities corresponding to the photoelectric cells.

This means that, in accordance with the abrupt variations, the layers of the material are not sewn. In order to prevent the disadvantages described above and to permit the edge of the material to be constantly guided towards the sewing mechanism of the machine even when there is a sudden variation in the curves or recesses of the profile itself, the technical problem to be solved is to slow down the speed of the sewing machine during the sudden variation in the profile.

SUMMARY OF THE INVENTION The technical problem described above is completely solved by the improvements that are the object of the present invention and that are applicable to an apparatus for guiding and sewing layers of fabric along an edge of any configuration. The apparatus includes a work-support plane for the layers of fabric to be sewn, a sewing machine with novel means for varying the operating speed, a device for guiding and clamping the work capable of guiding the edge of the material in the direction of the sewing mechanism of the machine. A first set of sensing elements is placed at a distance from each other transversely to the direction in which the material is advancing, in the vicinity of the sewing mechanism and is capable of sensing the changing curves or recesses in the profile of the material so that the orientation of the guiding and clamping devices can be varied accordingly. The improvements of the invention also include an additional set of sensing elements capable of sensing the abrupt variations in the profile of the material and of controlling the devices for varying the operating speed of the sewing machine so as to reduce the speed whenever there are abrupt variations in the profile of the material and which is capable of returning said speed back to the previous level when the curves and recesses of said profile are no longer changing.

These and other characteristics of the present invention will become clear upon reading the following detailed description of a preferred but not exclusive exemplified embodiment, illustrated purely by way of example on the attached drawings, in which:

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of the apparatus for guiding and sewing layers of fabric.

FIG. 2 is a perspective view showing the location of sensing means for detecting irregularities in the edge of the fabric to be sewn.

FIG. 3 is a perspective view showing elements of the apparatus in greater detail.

FIG. 4 is a perspective view showing the further detail of the apparatuses switching means; and

FIG. 5 is a diagramatical view of the control circuit for the apparatus DESCRIPTION OF THE PREFERRED EMBODIMENT In reference to FIG. 1, 1 indicates a support plane for work 2; this work 2 may consist of one or more layers whose edges must first be perfectly matched before they can be sewn together.

The borders of said layers may have a variable profile 3 of any desired configuration.

At one end of support plane 1 a traditional sewing machine 4 is fixed, for example of the cut-and-seam type for the forming of an overseam.

As can be better seen in FIG. 2, the sewing machine 4 includes a head with a base 5 and a standard 6 at the end of which are the known upper sewing elements including the pressor foot 7, and an upper feeding device 8 positioned forwardly of said upper sewing elements.

The sewing machine also has an electric motor 9 of a known type provided with an electromagnetic friction-brake clutch unit on whose driven shaft a sheave 11 is assembled and, which is operatively connected by a belt to the usual hand wheel 12 of the sewing machine.

The friction-brake clutch unit of motor 9 is of the type which permits obtaining two or more rates of revolution for the number of revolutions of the driven shaft and consequently of the sewing machine handwheel, while the number of revolutions of the electric motor remains the same.

In the friction-brake clutch unit, the number of revolutions of the driven shaft is varied by the relay control which is excited and deenergized with a preestablished frequency by the electromagnets.

According to one possible example of a variant, electric motor 9 can be any triphase asynchronous motor with a friction-brake clutch system of the mechanical type in which provision is made for the known rheostatic systems to regulate the speed of the motor itself. As is shown in FIG. 1, to the left of the sewing machine there is a box 13 which contains the electric controls for starting the electric motor of the sewing machine and for controlling other'elements which will be more fully described hereinafter.

Assembled to the frame that supports plane 1 and upwardly directed curved arm 14 is provided which extends over the head of the sewing machine.

Hinged to curved arm 14 is a second arm 15 which can rotate, with respect to curved arm 14, around a verticl axis 16; and said second arm 15 includes a handle 17 for effecting manual rotation thereof. Attached to the second arm 15, which is disposed forwardly of the sewing machine, are two tracks 18 and 19 located parallel to each other and to support plane 1.

On track 18 a carriage 20 is movable and includes a clamping device 21 consisting of a fixed clamp 22 that communicates with plate 1 and which is carried on a vertical supporting plate 50 (FIG. 3). This clamping device further includes a pivotable clamp 23 carried on an arm 51 of a bell crank type lever which is pivotably supported as at 53 to the vertical support plate 50. The other arm of this bell crank level is identified by numeral 54 and is pivotably connected to a piston 55 of a pneumatic cylinder 56 (FIG. 3) which is also fixed by any suitable means to the vertical supporting plate 50. The pneumatic cylinder 56 receives its source of air through a line or flexible tube 24 having a plurality of spiral windings that enable it to follow the carriage 20 during its movement.

In a diametrically opposed location relative to arm 51 of the bell crank level 52 a hook 25 is provided having a detent 57 (FIG. 3) on the free end thereof adopted for engagement with a detent 58 of conforming configuration connected to an end stop or limit switch 27 that is selectively located on the track 18 (FIG. 1).

As shown in FIG. 3, the vertical supporting plate 50 includes plate members 59 and 60 fixed thereto which carry roller elements 61 on their free ends which are disposed so as to engage different surfaces of the track 18. These roller elements serve to provide unrestricted movement of the carriage and'to prevent any possible tilting thereof on track 18.

Referring to FIGS. 3 and 4, plate member 60 is adapted to engage and depress an actuator 62 of a microswitch 28 located adjacent the end of the track 18 disposed in close proximity with the sewing machine and serves to actuate in sequence both the pneumatic cylinder 56 and a pneumatic propelling unit 29.

Above the carriage 20 an L-shape block member 63 is provided which includes an internal and horizontally extending cavity 64 into which the pneumatic propelling unit 29 (FIG. 4) is caused to enter when the carrige 20 reaches the limit of its travel. At this time a jet of air under pressure is released by the pneumatic propelling unit 29 within the cavity 64 and is effective in reversing the direction of movement of the carriage so as to return it to the position in readiness for repeating the cycle. During the initial reverse movement of the carriage 20 the detent 57 is caused to engage detent 58 on a hinge member 26. Both the microswitch 28 and the pneumatic propelling unit 29 are supported on a bracket 65 (FIG. 4) having slots 66 which by suitable means (not shown) is assembled to the second arm 15. Slots 66 provide a means whereby the position of the microswitch 28 can be adjusted to the most desirable operating location. Another carriage 30 is mounted and movable on track 19. This carriage 30 being of a known type and similar to carriage 20 includes a pair of clamps 31 similar in control and operation to clamp 21 and have the function of gripping the material at an intermediate position along its length, particularly in the case where the edges of the layers to be sewn have different profiles. A limit-switch 32 is provided on track 19 and its position may be selectively located on said track; also said limit-switch 32 is provided with means for engaging carriage 30.

At the beginning of track 19, near the sewing machine, a microswitch 33 and a known pneumatic propelling unit 34 are installed which are capable of driving carriage 30 to the end of track 19 into the position at the end of the course.

Both tracks 18 and 19, which are rigidly joined together, can rotate around vertical axis 16 and said rotation, in addition to being obtained manually with handle 17, is accomplished automatically via known pneumatic means which are not illustrated here.

As is illustrated more clearly in FIG. 2, and disposed forwardly of the upper feed device 8 of the sewing machine, in support plane 1, there is a aperture 35 for housing a first and second pair of photoelectric cells 36-37 and 38-39, respectively that are positioned transversely to the direction in which the material is advancing and over which a lamp 40 supported by an arm 41 is positioned.

The two central photoelectric cells 36 and 37 have the known function of detecting the variations in the profile 3 of the material and of consequently controlling the known pneumatic means which cause the tracks to rotate around the axis 16 in order to guide the edge of the material in the direction of the sewing device.

The two external photoelectric cells 38 and 39, being at a greater distance from each other, have the function of detecting the abrupt variations in profile 3 and control the means provided for reducing the speed of the drive shaft of the friction-brake unit of motor 9 or of the motor itself whenever said variations are sensed and of subsequently returning the speed back to the rated operating speed whenever said variations cease.

The way in which the apparatus operates will now be described. An operator after closing a main switch 67 (FIG. 5) carried on the box 13 aligns the edges of the layers of fabric before inserting them under the pressure foot 7 and then by means of a manual control 68 in said box 13 lowers said pressure foot into engagement with the fabric to be sewn. Actuation of the hand control 68 energizes a relay 69 which closes its own holding contact 70. Energizing relay 69 also actuates another contact 71 from the feed circuit of a relay 72 toward a feed circuit of a relay 73 having a control 74 preferably of the treadle type. The actuation of the holding contact 71 causes the deenergizing of relay 72 which is normally energized to actuate a solenoid controlled valve 75 that is operatively associated with the pneumatic circuit to control the raising of the presser foot 7 at the end of the sewing cycle. Consequently the deenergizing of relay 72 causes the opening of its contact 76 and the lowering of the pressure foot 7 to a position of engagement with the fabric to be sewn. At

this point the operator effects activation of the clamps 31 by activation of a hand control 77 that controls the energizing of a relay 78 and which is effective in closing its own holding contact 79 as well as actuation of the microswitch or limit switch 33 in series therewith. Another contact 80 is provided for actuating a solenoid controlled valve 81 which controls the feeding of a pneumatic cylinder 31a that is operatively connected to the clamps 31. The closing of the contact 80 energizes a solenoid controlled valve 82, forming a part of the pneumatic circuit, which is effective in actuating the pneumatic propelling unit 34 upon actuation of microswitch 33.

The operator after positioning the fabric for holding by the clamp 21 and actuating control 74 cause actuation of said clamp 21 and the starting of the electric motor 9. The actuation of control 74 controls the energizing of relay 73 which closes its own contact 83 that is in series with the microswitch 28. Additionally, a contact 84 is provided for actuating a solenoid controlled valve 85 which controls the feeding of the pneumatic cylinder 56 that is operatively connected to the clamp 21. With the closing of the contact 84 energization of a solenoid controlled valve is also affected, this value being in the pneumatic unit 29 is prepared for operation when the clamp 21 initiates actuation of the microswitch 28. More precisely the opening of the microswitches or limit switches 28 and 33 causes the deenergizing of the solenoid controlled valves 86 and 81 and the release of a predetermined quantity of air by the pneumatic propelling units 29 and 34 so as to effect the return of the carriages 20 and 30 to their starting positions. The electric motor 9 functions normally until actuation of the microswitch 28 which is controlled by the carriage .20. When a variation occurs in the profile of the fabric being sewn and the variation is slight, light to the photoelectric cell 37 becomes interrupted and the photoelectric cell 36 remains energized to effect operation of a pneumatic device 87 which includes a pneumatic cylinder having a piston 88 operatively connected to both tracks 18 and 19. These tracks 18 and 19 are rotatable about a vertical axis 16 in one direction or the other as dictated by the variation in the profile 3 of the fabric being sewn.

During normal sewing light to the photoelectric cell 36 is interrupted and if a variation in the profile 3 exposes said photoelectric cell 36 to its source of light it becomes energized to effect the closing of a contact 89. The closing of contact 89 actuates a solenoid controlled valve 90 that is normally closed, and causes compressed air to enter and operate the pneumatic cylinder 87. The pneumatic cylinder being operated in this manner effects shifting or movement of the tracks 18 and 19 toward the right, which movement continues until the fabric being shifted by said tracks interrupts the light directed to the photoelectric cell 36. When light to the photoelectric cell 36 is interrupted, it is deenergized causing the opening of contact 89 and the deenergizing of the solenoid controlled valve 90. The deenergizing of the solenoid controlled valve 90 stops further movement of the tracks 18 and 19 by a shut off of air to the pneumatic cylinder 87 and said tracks remain stationary until a subsequent variation in the profile 3 occurs. If a variation in the profile 3 causes an interruption of light to the photoelectric cell 73, which is normally energized, then a contact 91 is opened causing the deenergizing of a solenoid controlled valve 92. The deenergizing of this solenoid controlled valve 92 causes compressed air to enter the pneumatic cylinder on the opposite side from which piston 88 extends, and is effective in moving the tracks 18 and 19 in the opposite direction or to the left until light to the photoelectric cell 37 is no longer interrupted.

When variations in the profile 3 require movement of tracks 18 and 19 for shifting the work and directing it toward the sewing mechanism for sewing along the variation in said profile, it is necessary that the rate of advance of the work be lessened as well as the speed of the motor 9 so that the piston 88 of the pneumatic cylinder 87 will stop said tracks in a position corresponding to the variation in said profile. If one of these variations causes the energizing of photoelectric cell 39 disposed to the left of photoelectric cell 36 there is a closing of a contact 93 and the energizing of an electric control 94 which decreases the speed of the electric motor 9 through the energizing and deenergizing with pre-established frequency the electromagnetic components of said motors clutch. It should be understood that changes in the speed of the electric motor can be obtained by other suitable means such for example as a pneumatic system.

If the variation in the profile 3 causes interruption of light to the photoelectric cell 38 disposed to the right of photoelectric cell 37, a normally closed contact 95 is opened to effect a reduction in rotating speed of the electric motor 9 through interruption of current to another electric control 96 whose function is similar to that of the electric control 94. The difference between the two electric controls 94 and 96 is that while one is normally deenergized during motor operation, the other is normally energized. When profile 3 of the material has been returned to the space between photoelectric cell 36 and photoelectric cell 37, tracks 18 and 19 will stop rotating around axis 16 and electric motor 9, and consequently the. sewing machine will once again start operating at the normal speed. Carriages 30 and 20 will continue to move along the tracks pulled along by the work' until reaching first carriage 30 and then carriage 20 the course limit, within a short distance of the sewing machine. In this position carriage 30 engages the microswitch 33 which causes the opening of clamp 31 and the invention of the pneu matic propelling unit 34; this pushes carriage 30 back against limit switch 32 which stops it and holds it back; still in this position, carriage 20 engages the microswitch 28, thus causing the opening of clamp 21 and the intervention of the pneumatic propelling unit 29; this pushes carriage 20 back against limit switch 27 which stops it by means of hook 25 and clasp 26. The sewing machine stops after the clamp 21 has been open for a certain period of time and the apparatus is then ready to start sewing on a new piece of material.

I claim:

1. An apparatus for guiding and sewing layers of fabric along an edge of irregular configuration comprising:

a. a support plane;

b. a sewing machine fixed to one end of said support plane having a drive motor of the electromagnetic friction brake-clutch type;

c. a support arm extending from said support plane having rotatable guide means carried thereby in a plane parallel with and spaced from said support plane;

e. sensing means carried by said support plane for detecting variations in the edge of the layer of fabric to be sewn which includes:

1. means operatively connected to said sensing means for rotating said rotatable guide means and clamping means carried thereby so as to orient the position of the fabric as it is advanced to said sewing machine;

2. means for reducing the speed of said sewing machine when the fabric is shifted to accommodate an acute variation in the edge of the fabric; and

3. means for returning said sewing machine to its initial operating speed upon completion of the sewing in the area of the acute variation in the fabric edge.

2. The apparatus for guiding and sewing layers of fabric according to claim 1 wherein said sensing means includes first and second pairs of photoelectric cells located adjacent to said sewing machine and disposed in a plane extending transversely to the direction of advance of the fabric to be sewn.

3. The apparatus for guiding and sewing layers of fabric according to claim 2 wherein said means for rotating said rotatable guide means and clamping means includes a pneumatic cylinder having a solenoid controlled valve in circuit with said first and second pairs of photoelectric cells.

4. The apparatus for guiding and sewing layers of fabric according to claim 2 wherein said means for reducing the speed of said sewing machine includes an electrical control in circuit with said second pair of photoelectric cells for effecting energizing and deenergizing with pre-established frequency the electromagnetic components of the clutch portion of said drive motor. 

1. An apparatus for guiding and sewing layers of fabric along an edge of irregular configuration comprising: a. a support plane; b. a sewing machine fixed to one end of said support plane having a drive motor of the electromagnetic friction brakeclutch type; c. a support arm extending from said support plane having rotatable guide means carried thereby in a plane parallel with and spaced from said support plane; d. means movable along said rotatable guide means for clamping the fabric and advancing the same toward said sewing machine along said support plane; e. sensing means carried by said support plane for detecting variations in the edge of the layer of fabric to be sewn which includes:
 1. means operatively connected to said sensing means for rotating said rotatable guide means and clamping means carried thereby so as to orient the position of the fabric as it is advanced to said sewing machine;
 2. means for reducing the speed of said sewing machine when the fabric is shifted to accommodate an acute variation in the edge of the fabric; and
 3. means for returning said sewing machine to its initial operating speed upon completion of the sewing in the area of the acute variation in the fabric edge.
 2. means for reducing the speed of said sewing machine when the fabric is shifted to accommodate an acute variation in the edge of the fabric; and
 2. The apparatus for guiding and sewing layers of fabric according to claim 1 wherein said sensing means includes first and second pairs of photoelectric cells located adjacent to said sewing machine and disposed in a plane extending transversely to the direction of advance of the fabric to be sewn.
 3. means for returning said sewing machine to its initial operating speed upon completion of the sewing in the area of the acute variation in the fabric edge.
 3. The apparatus for guiding and sewing layers of fabric according to claim 2 wheRein said means for rotating said rotatable guide means and clamping means includes a pneumatic cylinder having a solenoid controlled valve in circuit with said first and second pairs of photoelectric cells.
 4. The apparatus for guiding and sewing layers of fabric according to claim 2 wherein said means for reducing the speed of said sewing machine includes an electrical control in circuit with said second pair of photoelectric cells for effecting energizing and deenergizing with pre-established frequency the electromagnetic components of the clutch portion of said drive motor. 